The present invention relates to improvements in radio data communication systems which utilize a polling protocol, originating from a base station, to schedule and maintain communication with a number of remote transceiver units. More particularly, the present invention relates to a dormant polling protocol which schedules all communication on a heavily loaded communication channel, while permitting unscheduled communication whenever the communication channel is lightly loaded.
To establish communication, polling protocols require a base station to repeatedly poll each of the remote transceiver units being serviced. Even during periods when no communication is taking place, the base stations must still continue to poll, awaiting a response. This unproductive polling not only wastes the base station's energy (important when the base station is battery powered), but also unnecessarily dominates a communication channel so as to interfere with other communication on or near that channel.
In addition, polling protocols are most effective under conditions of heavy channel communication--where effectiveness is a measure of response time. During periods of light channel communication, a CSMA (carrier-sense multiple-access) type protocol which is initiated by the remote transceivers prove more effective than a polling protocol. However, neither of these types of communication protocols prove most effective under both heavy and light communication loading.
Accordingly, it is an important object of the invention to provide a dormant polling protocol that effectively operates during periods from heavily to lightly loaded conditions.
Another object of the invention is to provide a radio data communication system utilizing a dormant polling protocol to efficiently conserve transmission energy.
A further object of the invention is to provide a radio data communication system having a dormant polling protocol that only utilizes a communication channel when necessary.
A further object of the invention is to provide a radio data communication system which switches between one type of communication protocol to another in response to channel loading characteristics.
Another object of the invention is to provide a radio data communication system which automatically chooses between a polling protocol and a remote initiated protocol to optimize channel efficiency.
Another object of the invention is to provide a radio data communication system that manages communication on a communication channel using a first protocol during periods of higher channel loading and a second protocol during periods of lower channel loading.
Other objects, features and advantages of the present invention will be apparent from the following detailed description taken in connection with the accompanying drawings, and from the respective features of the appended claims taken individually and in cooperative combinations.